For nearly a century, pump jacks have been used in the production of hydrocarbons from downhole formations. Such jacks are seen atop many oil fields, their rhythmic movements common. It is well known how the pump jacks work, which is by moving sucker rods up and down within the wellbore. For the same near century, the pumps have worked very well doing precisely that, pumping.
More modern well systems while still employing pump jacks also are instrumented extensively downhole. This requires substantial amounts of available power in the downhole environment. Power is for the most part delivered from the surface but due to the small amount of available space in the hole, allocation of such space is a source of trepidation. Since the hydrocarbon recovery art is always in search of improved means to produce hydrocarbons, any reduction in components needed within the cross-section of the wellbore would be well received.